Conventionally manufactured chocolate consists of sugars, cocoa solids and protein (usually from milk) homogeneously dispersed in fats and fatty substances originating from cocoa butter. Chocolate analogues contain other vegetable fats in partial/total replacement of the cocoa butter fat. Often the continuous fat phase also contains dairy fat.
Cocoa butter typically starts to soften at about 28° C., with consequent loss of the mechanical strength of the chocolate. This means that at the high ambient temperatures frequently encountered in tropical countries, chocolate becomes sticky or even runny. It tends to stick to the wrapper and fall apart when the wrapper is removed, leaving a semi-liquid mass that can often only be eaten with a spoon if cleanliness is desired. Enrobed chocolate products typically lose integrity under these conditions, with their contents often leaking and individual units tending to stick together in the packaging. Chocolate also loses the ‘snap’ that is an important (and pleasurable) textural characteristic of chocolate stored and eaten under cooler conditions.
Attempts to produce a chocolate that is resistant to heat are numerous. The approaches most widely used can be divided two main groups: 1) incorporation of high-melting point fats; and 2) creation of a three-dimensional matrix or network of sugar crystals or protein particles that will act as a sponge and hold the fat—thus maintaining the structure of the product even on melting of the fat. Over the last century many different methods have been reported.
There are two major drawbacks to the use of high-melting fats in chocolate. Namely that food regulations in many countries restrict the use of substitutes for cocoa butter in chocolate. Secondly, the high-melting point fats in chocolate-like products give an unpleasant waxy mouthfeel.
Many methods have been described for causing accretion of sugar crystals by adding water or a polyol to chocolate, as originally disclosed in DE 389 127 (1919). CH 409,603 (1962) describes the direct incorporation of water into liquid chocolate mass during production causing a rapid increase in viscosity. As a result, it is impossible to pour the material into moulds or use for enrobing.
EP0189469 (1985) describes the mixing of a liquid polyol with tempered conventional chocolate mass before depositing it into molds. Polyols that are liquid at ambient temperatures (such as glycerol) are preferred, though the patent teaches that higher melting polyols (such as sorbitol) can also be used. The mixture is held at slightly elevated temperatures (24° C. to 35° C.) for a short period of time during which the viscosity rises. This is stated to be the result of a chemical reaction between the fat and the polyol. The time and temperature of the holding period are critical parameters that control the viscosity increase—the viscosity must remain low enough for the subsequent molding or enrobing operations.
In the method described by U.S. Pat. No. 5,445,843 a polyol (such as glycerol) is encapsulated by emulsifying it with a liquid fat (such as molten cocoa butter) and lecithin as an emulsifier, then spray-chilling the emulsion. The emulsion “capsules” (which have an average diameter 100 microns) are added to liquid chocolate mass to achieve a polyol content of from 0.2 to 5% by weight. The product was reported to have remained liquid for several minutes.
The use of emulsification to avoid too rapid an incorporation of water into the chocolate mass is described in U.S. Pat. No. 4,446,166. An oil-in-water emulsion (typically 50% water, 50% fat) is prepared with cocoa butter using lecithin as the emulsifier. The emulsion is cooled and milled to give partially or entirely solid particles that are then added to the chocolate mass at levels of between 2 and 10%. Once incorporated in the warmer liquid chocolate mass, the emulsion particles will melt, releasing the water droplets. A disadvantage of this method is the need to guarantee a homogeneous distribution of the emulsion particles before they melt. Premature release of water causes a sudden increase in viscosity that renders the chocolate unsuitable for molding or enrobing.
EP 0297054 describes a method for homogeneously dispersing water by using an aqueous foam. The foam is stabilized with an edible foaming agent (such as egg albumin) and added to conventionally prepared chocolate mass after tempering. The foam is added at levels that deliver from 0.5 to 2% of water, reportedly with no noticeable increase in viscosity to provide a treated chocolate usable for molding or enrobing. The trapped gases can be removed from the still liquid product by exposing it to reduced pressure. EP0407347 describes a similar method.
EP0393327 discloses another variation in which the aqueous phase of the water-in-oil emulsion contains sugars (such as sucrose or glucose) or polyols (such as sorbitol). The emulsion is prepared with 30 to 60% fat using emulsifying agent at a level of 0.1 to 3%. Described suitable emulsifying agents are lecithin, glycerol fatty acid ester, polyglycerol fatty acid ester, polyglycerol condensed ricinoleic acid ester and sucrose fatty acid ester that has an HLB not more than 7. The level of sugar or polyol in the aqueous phase of the emulsion can be between 20 and 60% and the level of water between 15 and 25%. The sugar or polyol in the aqueous phase is reported to provide smoother texture to the heat-stable chocolate mass. A storage period of about 20 days, however, is required for proper development of internal structure.
A similar method is disclosed in EP0442324, whereby an oil-in-water emulsion is prepared by mixing 30-80% of an oil or fat (for example, cocoa butter) in water containing a small amount of a suitable emulsifier. This emulsion is mixed at a level of about 5% with a conventionally manufactured and tempered chocolate mass that is then molded. It is stated to be important to control the temperature to be no higher than 90° F. to keep the oil-in-water emulsion stable. The homogeneously dispersed water generates a viscosity increase of the chocolate mass during solidification of the finished product. However, it is still necessary to store the molded product for several days to establish heat stability.
U.S. Pat. No. 5,486,376 describes the use of water-in-oil microemulsions to introduce finely dispersed water into chocolate mass. Similarly, U.S. Pat. No. 6,159,526 describes addition of water to the chocolate as a water-in-oil emulsion stabilized by sucrose fatty acid esters (HLB<3). U.S. Pat. No. 6,159,526 is concerned primarily with adding water-based flavors to chocolate.
WO 93/06737 describes methods for making gels/pastes by adding water to “Raftiline” (inulin), starches (potato and corn), “Splendid” (pectin), or gum Arabic. The paste is then mixed into tempered chocolate that is molded.
U.S. Pat. No. 5,468,509 describes a method for adding up to 16% water to chocolate. The chocolate supposedly remains moldable. Two mixtures are prepared. (1) Cocoa is coated with cocoa butter in the presence of an emulsifier and (2) water, a sweetener and milk solids are blended to form an aqueous phase. The two are gently blended and the product molded.
U.S. Pat. No. 5,965,179 aims to circumvent the problems of viscosity increase on the addition of water to chocolate by use of an extruder for processing the chocolate. The water is added as an aqueous gel with microcrystalline cellulose. This gel is injected into the chocolate using a twin-screw extruder so as to form a viscous product containing 3 to 20% of added water.
US2005/0118327 describes the preparation of gel beads comprising 20-50% sugar or polyol, water, emulsifying agent and a gelling agent (hydrocolloids). The gel beads are formed by dispersing a hot aqueous sol (90° C.-95° C.) in a liquid fat in a high shear mixer, to form an emulsion, and then cooling to get gelification of the beads. The gel beads dispersed in fat are blended into molten chocolate mass. One drawback is that the release of the sugar/polyol syrup from the gel beads, requires activation. US2005/0118327 teaches the activation of gel bead degradation by freezing a temperatures of −5° C. to −15° C. It is reported that without this cooling it is necessary to store the products for 10-14 days to develop shape retention properties.
In another approach WO91/19424 describes the preparation of gel beads comprising alginate or pectate, divalent metal ions and a sequestrant for the metal ions. The gel beads are used as fat substitutes.
EP0688506 describes the preparation of gels comprising polyol or polyol/water with gelling agents and alkali or alkali-earth metal salts. The gels are produced by heating to temperatures of 120° C. and are then frozen in liquid nitrogen, before addition to liquid chocolate.
These prior art references have drawbacks such as the release of water into the chocolate mass, which occurs early in the process and is not retarded for long enough for the material to be used for typical enrobing processes; the dispersion and release of water is not under sufficiently fine control to avoid development of unpleasantly gritty textures in the final product; and/or activation or an inconveniently long storage time is required for full development of the structures required to provide stability. Many of the processes are complex, or require additional steps in the production procedure, and/or require the use of emulsifiers and/or gelling agents.
Accordingly there is an ongoing need to provide a tropicalizing agent that delays any substantial increase in viscosity so the materials can be used for conventional molding or enrobing processes and that provides a suitable texture and stability, or integrity, in a chocolate product.
It is an aim of the present invention to provide a tropicalizing agent which minimizes or overcomes one or more disadvantages of the above-mentioned references.
It would be advantageous to provide a tropicalizing agent that provides a heat shape stability, or integrity, in a tropicalized product, and that may be easily industrialised at a reasonable cost.
It would be advantageous to provide a tropicalizing agent that delays any substantial increase in viscosity so the materials can be used for conventional moulding or enrobing processes and that provides heat shape stability, or integrity, in a chocolate product, after a reasonable storage time, without compromising the organoleptic parameters.